Moms aren't the only ones riding high on "Fifty Shades of Grey." Sex toy sales are surging as more couples add handcuffs and riding crops to their repertoire.

At San Francisco-based Good Vibrations, sales of bondage sex toys have increased 65 percent and erotica 50 percent since "Fifty Shades" rose to the top of the best-seller lists this spring with its graphic tale of an ingenue submitting to the sexual games of a powerful man, introducing mainstream audiences to themes of BDSM (an acronym encompassing bondage and discipline, domination and submission and sadism and masochism). At New York-based Babeland, bondage toy sales have grown 40 percent, with certain paddles, blindfolds and a spiky metal tool called a pinwheel experiencing triple-digit increases, said public relations director Pamela Doan. The store also is offering free classes based on the "Fifty Shades" sex scenes, drawing 125 people to the first event and 400 RSVPs to the second — far more than the 25 to 30 attendees events typically draw, Doan said.

Kegel balls, the beads mentioned in "Fifty Shades" that strengthen pelvic floor muscles for improved orgasms, have become particularly popular. Manufacturer Fun Factory has seen sales of its Smart Balls rise 350 percent this spring over last, and its German factory has had to pick up night shifts to keep up with demand, said marketing director Emilie Rosanvallon.

"I have never seen anything like this," said Susan Wright, founder of the National Coalition for Sexual Freedom, an advocacy group for BDSM. "We have tracked media coverage of BDSM since the '90s, and it is just astonishing how many people are talking about this."

Just as "Sex and the City" prompted a run on Rabbit vibrators, "Fifty Shades" is giving people — and women in particular — permission to venture into new erotic territory they may have previously been too shy to explore, said Carol Queen, staff sexologist at Good Vibrations.

Though it's hardly the first book on the topic, and movies such as "91/2 Weeks" and "The Secretary" depicted steamy sadomasochistic scenes, "Fifty Shades" managed to hook mainstream audiences with its romance novel tropes, providing a bridge to erotica, Queen said.

Rebecca Salerno said she had never set foot inside an adult toy store until her co-workers turned her on to the book and she went to Babeland's "Fifty Shades of Hot Sex" class. The book, perhaps because it's so silly, she said, made her feel more comfortable talking about and experimenting with sex toys, "and it gave so many good ideas."

Salerno, 29, said she has a list of toys she's saving up for, including a pair of fur-lined handcuffs. Though one of the chief criticisms of the book has targeted the sexual submission of the woman, Salerno considers that its No. 1 appeal.

"I think there's a lot of pressure on women in general to have it all and be it all, and sometimes you just want a man to know what he's doing," said Salerno, who works as an executive assistant at an Internet startup in Manhattan.

Queen praises this newfound sexual adventurousness for couples looking to get frisky or lift their sex lives out of a rut. But she cautions that "Fifty Shades" is not a how-to manual for BDSM, which involves a power-exchange relationship between a dominant and submissive partner. Queen's concern is that people will try something without really knowing how to get into it — or out of it — and will be disappointed or put off, which can further dim their sexual fires.

There are safety logistics beginners might not be aware of: For example, metal handcuffs are a no-no because they can cause permanent nerve damage, and using silk scarves or ties as restraints is inadvisable because the knot on slippery fabrics gets tighter and tighter, Queen said.

Safety, trust and consent are key tenets of BDSM, which relies on couples having a safe word to indicate that the play needs to end, be it because they're uncomfortable or because they realize they forgot the roast in the oven. ("I had a friend who used 'chrysanthemum,'" Queen said.)

For couples who want to test the waters, start with a list of what you want, said Lou Paget, a Los Angeles-based certified sex educator and author of many books on sexuality. Do you want to be blindfolded? Restrained? The anticipation and negotiation with your partner is a large part of what makes it so hot, she said. Fantasizing or role-playing alone are enough for many people, Paget said, but for those who do want physical toys she recommends Sportsheets, a beginner-friendly line of fabric restraints and Velcro cuffs.

For established practitioners, the increased curiosity is a mixed blessing. Some worry about being misunderstood or that weekend warriors may not grasp the nuances. But at the Center for Sex Positive Culture, a nonprofit in Seattle that offers BDSM education, Executive Director Allena Gabosch is cheered by the increase in women and couples who have expressed interest and that there's more "Mr. and Mrs. Joe Suburbia."

"It's a bizarre phenomenon, and I welcome the whole thing," Gabosch said. "This is just giving people a way to discover who they really are."